From 28877b0fcdde7bd5c7ff3fc9305fc28ad9ba17cf Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 11 Aug 2023 15:12:17 +1000 Subject: [PATCH] tap: Clean up tap reset path In tap_handler() if we get an error on the tap device or socket, we use tap_sock_init() to re-initialise it. However, what we actually need for this reset case has remarkably little in common with the case where we're initialising for the first time: * Re-initialising the packet pools is unnecessary * The case of a passed in fd (--fd) isn't relevant * We don't even call this for pasta mode * We will never re-call tap_sock_unix_init() because we never clear fd_tap_listen In fact the only thing we do in tap_sock_init() relevant to the reset case is to remove the fd from the epoll and close it... which isn't used in the first initialisation case. So make a new tap_sock_reset() function just for this case, and simplify tap_sock_init() slightly as being used only for the first time case. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- tap.c | 52 +++++++++++++++++++++++++++++----------------------- 1 file changed, 29 insertions(+), 23 deletions(-) diff --git a/tap.c b/tap.c index 7261370..279440b 100644 --- a/tap.c +++ b/tap.c @@ -1236,19 +1236,14 @@ void tap_sock_init(struct ctx *c) tap6_l4[i].p = PACKET_INIT(pool_l4, UIO_MAXIOV, pkt_buf, sz); } - if (c->fd_tap != -1) { - if (c->one_off) { /* Passed as --fd */ - struct epoll_event ev = { 0 }; + if (c->fd_tap != -1) { /* Passed as --fd */ + struct epoll_event ev = { 0 }; + ASSERT(c->one_off); - ev.data.fd = c->fd_tap; - ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP; - epoll_ctl(c->epollfd, EPOLL_CTL_ADD, c->fd_tap, &ev); - return; - } - - epoll_ctl(c->epollfd, EPOLL_CTL_DEL, c->fd_tap, NULL); - close(c->fd_tap); - c->fd_tap = -1; + ev.data.fd = c->fd_tap; + ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP; + epoll_ctl(c->epollfd, EPOLL_CTL_ADD, c->fd_tap, &ev); + return; } if (c->mode == MODE_PASST) { @@ -1259,6 +1254,26 @@ void tap_sock_init(struct ctx *c) } } +/** + * tap_sock_reset() - Handle closing or failure of connect AF_UNIX socket + * @c: Execution context + */ +static void tap_sock_reset(struct ctx *c) +{ + if (c->one_off) { + info("Client closed connection, exiting"); + exit(EXIT_SUCCESS); + } + + if (c->mode == MODE_PASTA) + die("Error on tap device, exiting"); + + /* Close the connected socket, wait for a new connection */ + epoll_ctl(c->epollfd, EPOLL_CTL_DEL, c->fd_tap, NULL); + close(c->fd_tap); + c->fd_tap = -1; +} + /** * tap_handler() - Packet handler for AF_UNIX or tuntap file descriptor * @c: Execution context @@ -1276,15 +1291,6 @@ void tap_handler(struct ctx *c, int fd, uint32_t events, if ((c->mode == MODE_PASST && tap_handler_passt(c, now)) || (c->mode == MODE_PASTA && tap_handler_pasta(c, now)) || - (events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR))) { - if (c->one_off) { - info("Client closed connection, exiting"); - exit(EXIT_SUCCESS); - } - - if (c->mode == MODE_PASTA) - die("Error on tap device, exiting"); - - tap_sock_init(c); - } + (events & (EPOLLRDHUP | EPOLLHUP | EPOLLERR))) + tap_sock_reset(c); }